Created attachment 1355 [details]
Patch to fix atomicio and atomiciov non-polling spin

atomicio contains the following in the read/write loop:

-----
                case -1:
#ifdef EWOULDBLOCK
                        if (errno == EINTR || errno == EWOULDBLOCK)
#else
                        if (errno == EINTR)
#endif
                                continue;
                        if (errno == EAGAIN) {
                                (void)poll(&pfd, 1, -1);
                                continue;
                        }
                        return 0;
-----

On systems where errno is set to EWOULDBLOCK we spin on the read or write without polling.  On many other systems (Linux, Solaris, IRIX, ...) EWOULDBLOCK is defined as EAGAIN, and when errno is set to EAGAIN we spin on the read or write without polling.

Please see patch.

thanks,

--ben